Wide-angle objective

ABSTRACT

A wide-angle objective composed of six components separated from each other by air spaces and located three at the object side of the diaphragm and three at the image side of such diaphragm, said six lens components taken in consecutive order from the side of the object comprising: a first lens component composed of one or more dispersing meniscus lens members curved towards the object side; a second lens component which follows a larger air space composed of a meniscus lens component curved towards the object side; a third lens component which follows an air space and possessing a collecting refractive index and having a strongly convex curved outer surface facing the object side and further having a concave cemented surface facing the object side which at the side of the object possesses a greater refractive index than at the image side; a fourth lens component which follows the diaphragm space, said fourth lens component having a collecting refractive index and a strongly convex curved outer surface which faces the image and further possesses a concave cemented surface facing the image and which at the side of the image exhibits a greater refractive index than at the side of the object; a fifth lens component which follows an air space and comprising a meniscus lens component which is curved towards the image and assembled from at least one dispersing and collecting lens and; a sixth lens component which follows a larger air space and composed of one or more dispersing meniscus lens members curved towards the image.

United Sta 1,2

Bertele [54] WIDE-ANGLE OBJECTIVE [72] Inventor: Ludwig Bertele,Heerbrugg, Switzerland [73] Assignee: Firms Wlld l-leerbrugg AG,Heerbrugg, Switzerland [52] US. Cl. .t ..350/2l5, 350/214 [51] Int. Cl...G02b 9/62 [58] Field of Search ..350/214, 215

[56] References Cited UNITED STATES PATENTS 3,630,600 12/ l 971 Bertele..350/2 1 5 Primary Examiner-David Schonberg Assistant Examiner-Paul A.Sacher Attorneywemer W. Kleeman ABSTRACT A wide-angle objective composedof six components 7 U," [451 Oct. 24,1972

separated from each other by air spaces and located three at the objectside of the diaphragm and three at' component which follows a larger airspace composed v of a meniscus lens component curved towards the objectside; a third lens component which follows an air space and possessing acollecting refractive index and having a strongly convex curved outersurface facing the object side and further having a concave cementedsurface facing the object side which at the side of the object possessesa greater refractive index than at the image side; a fourth lenscomponent which follows the diaphragm space, said fourth lens componenthaving a collecting refractive index and a strongly convex curved outersurface which faces the image and further possesses a concave cementedsurface facing the image and which at the side of the image exhibits agreater refractive index than at the side of the object; a fifth lenscomponent which follows an air space and comprising a meniscus lenscomponent which is curved towards the image and assembled from at leastone dispersing and collecting lens and; a sixth lens component whichfollows a larger air space and composed of one or more dispersingmeniscus lens members curvedtowards the image.

5Clalms,9DrawlngFig|ues Patent e d Oct. 24, 1972 9 Sheets-Sheet 5Patented Oct. 24,1972

9 Sheets-Sheet 7 -Patented Oct. 24,1972 3,700,312

9 Sheets-Sheet 8 r 1| l'( m H I 1 plication of my commonly assigned,copending application, Ser. No. 816,218, filed Apr. 15, 1969, andentitled Wide-Angle Objective."

CROSS-REFERENCE TO RELATED CASE The present application is acontinuation-in-part ap- BACKGROUND AND DISCLOSURE OF THE INVENTION Thepresent invention relates to an improved wideangle objective composed ofsix components separated from each other by air spaces and located threeat the object side of the diaphragm and three at the image side of suchdiaphragm.

. According to the teachings of this invention the individual lenscomponents are constructed and arrangedv in the following manner:

a. the first lens component A is one or a number of dispersing meniscuslens members curved towards the object side;

b. the second lens component B which follows a larger air space is alsoa meniscus lens component which is curved towards the object side; thethird lens component C follows an air space which is greater than 0.005F and smaller than 0.17 F, this third lens component possessing acollecting refractive index and having a strongly convex curved outer orextreme surface facing the object side having a radius of curvaturelying in a range between 0.26 and 0.95 F, and further has a concave orhollow cemented surface facing the object which at the side of theobject possesses a clearly greater refractive index than at the imageside and has a radius of curvature lying in a range between 0.30 and0.72 F;

the fourth lens component D follows the diaphragm space, this fourthlens component having a collecting refractive index and a stronglyconvex curved outer or extreme surface which faces the image andpossessing a radius of curvature between 0.24 and 1.05 F and furtherpossesses a concave or hollow cemented surface facing the image andwhich at the side of the image exhibits a clearly greater refractiveindex than at the side of the object and has a radius of curvature whichis in the range between 0.28 and 0.60 F;

e. the fifth lens component E follows an air space which is greater than0.00 F and smaller than 0.25 F, this fifth lens component definingmeniscus lens component which is curved towards the image and isassembled from at least one dispersing and collecting lens;

f. the sixth lens component F follows a larger air space and defines oneor a number of dispersing meniscus lens members which are curved towardsthe image;'

g. the spacing of both outer or extreme surfaces of 60 the cementedcollecting lens components C and D which face away from the diaphragm isin a range between 0.35 F and 0.90 F;

h. the radius of curvature of the convex surface of the third lenscomponent C is in a range amounting to one to three times the axialthickness of this third lens component;

,- i. the radius of curvature of the convex surface of the fourth lens.component D is in a range between one to three times the axial thicknessof such fourth lens component; and

j. the outside radius of the objective at the side of the image is lessthan the outside radius at the side of i the object.

Objectives with these features constitute an improvement upon theobjective illustrated in FIG. 1 of my aforementioned US. Pat. No.2,734,424, granted Feb. 14, 1956. Such lens sequence which has provenitself in practice nonetheless possesses certain drawbacks, especiallywith regard to correction of the spherical and spherochromaticaberration. It has been found that air spaces or layers in the form of ameniscus concave towards the diaphragm instead of cemented surfacesconcave towards the diaphragm quite considerably improve the course ofthe curves for the aforementioned aberrations without having to takeinto account any other drawbacks. These measures are advantageousthroughout widely extending boundries.

Additional experiments have shown that the comatic correction for thedifferent image angles can be carried out much better if there isdispensed with the extensive symmetry contemplated by the examples ofthe aforementioned U.S. Pat. No. 2,734,424, and specifically, especiallywith regard to the curvature of the boundry surfaces of the small airspace between the collecting lens components enclosing both sides of thediaphragm and the neighboring meniscus-shaped lens components. Thedeviation from the symmetrical arrangement is manifested in that thedifference of the radii of curvature of the surfaces bounding theseaforementioned air spaces to both sides of the diaphragm is greater than1.35 times the corresponding difference at the object side of thediaphragm.

The invention is illustrated by fourteen examples shown in FIGS. 1through 9 of the accompanying drawings, each relating to an objectivehaving a focal length F equal to 100 mm, an image angle of and anaperture ratio of about 1:4 in Examples 1 to 7 and 12, and 1:5.6 inExamples 8 to 11 and l3, 14. In each Figure the six successivecomponents starting from the object side are designated by the referencecharacters A, B, C, D, E, and F. The reference character L inconjunction with a number is used to denote the individual lenses.Furthermore, in the Examples given hereinafter, the symbols r representthe radii of curvature, the symbols d represent the thickness of thelenses, and the symbols 1 the air spaces. The symbol n represents therefractive index for the helium line, and the symbol 1),, represents theAbbe number. The numbering is consecutive from the side of the object,and reference character Bl denotes the diaphragm.

Considering now the drawings, each of the wideangle objectives will beseen to be composed of six components A, B, C, D, E and F separated fromeach other by air spaces. Three of the lens components, namelycomponents A, B, C, are located at the object side of the diaphragm B1and the other three lens components, D, E and F are disposed at theimage side of such diaphragm. The first lens component A reckoned fromthe side of the object may be one or a number of dispersing meniscuslens members curved towards the side of the object. Hence, such firstlens component A may consist of a single dispersing meniscus lens memberL, as in FIGS. 1 to 4 and 6 to 9 inclusive, or two dispersing meniscuslens members L, and L, as in the arrangement of FIG. 5.

After a larger air space I (FIGS. 1-4 and 6-9) or 1 (FIG. there followsthe second lens component B which is also a dispersing meniscus lenscomponent curved towards the object side. In the embodiments depicted inFIGS. 1, 4, 5, 6, 7 and 9 such second lens component B consists of asingle dispersing lens member L whereas in the embodiment of FIGS. 2, 3and 8 such consists of the cemented lens members L and L The third lenscomponent C follows an air space 1 (FIGS. 1-4 and 6-9) or l (FIG. 5)which is greater than 0.00 F and smaller than 0.17 F. This third lenscomponent C comprises the lens members L L (FIGS. 1, 4, 6, 7 and 9) orlens members L L (FIGS. 2, 3, 5 and 8) and possesses a collectingrefractive index. Moreover, lens component C has a strongly convexcurved outer or extreme surface facing the object side having a radiusof curvature which is in a range between 0.26 and 0.95 F. Further, thisthird lens component C possesses a cemented surface which is com cave orhollow towards the object side and which at the side of the objectpossesses a clearly greater refractive index than at the image side andhas a radius of curvature lying in a range between 0.30 and 0.72 F.

The fourth lens component D follows the diaphragm region or space andcomprises the cemented lens member L L (FIGS. 1, 4, 6 and 7) or the lensmembers L L (FIGS. 2, 3 and 5) or the lens members L L and L (FIG. 8) orthe lens members L5, L and L (FIG. 9). This fourth lens component Dpossesses a collecting refractive index and has a strongly convex curvedouter or extreme surface which faces the image and possesses a radius ofcurvature lying in a range between 0.24 F and 1.05 F and furtherpossesses a cemented surface which is concave or hollow in the directionfacing the image and which at the side of the image exhibits a clearlygreater refractive index than at the side of the object and has a radiusof curvature which is in a range between 0.28 and 0.60 F.

The fifth lens component E follows an air space 1., (FIGS. 1-4 and 6-9)or (FIG. 5) which is greater than 0.00 F and smaller than 0.25 F. Thisfifth lens component defines a meniscus lens component which is curvedtowards the image and is assembled from at least one dispersing andcollecting lens component. In FIGS. 1, 4, 6, and 7 lens component Econsists of the cemented lens elements L and L in FIGS. 2, 5 and 9 ofthe cemented lens elements Lg and L in FIG. 3 of the cemented lenselements L L and L and in FIG. 8 of the cemented lens elements L and LThe sixth lens component F follows a larger air space 1 (FIGS. 1-4 and6-9) and L (FIG. 6) and defines one or a number of dispersing meniscuslens members which are curved towards the image. In FIG. 1 lenscomponent F consists of lens member L in FIGS. 2 and 5 the lens membersL and L in FIGS. 4, 6 and 7 the lens members 1 and L in FIGS. 3 and 8the lens members L and L and in FIG. 9 the lens member L The spacing ofboth outer or extreme surfaces of the cemented collecting lenscomponents C and D which face away from the diaphragm is in a rangebetween 0.35 and 0.90 F. The radius of curvature of the'convex surfaceof the third lens component C is in a range amounting to one to threetimes the axial thickness of such third lens component. The radius ofcurvature of the convex surface of the fourth lens component D is in arange between one to three times the axial thickness of such fourth lenscomponent. Further, the outside radius of the objective at the'side ofthe image is less than the outside radius at the side of the object.

With respect to the correction possibilities, above all for the largeimage angle,favorable conditions prevail if the lens component F iscomposed of two meniscus lenses separated by an air space.Notwithstanding the small diameter of the diaphragm or aperture bundle,such a division is more advantageous at this location of the objectivethan at the lens component A. The number of independent or freestandingdispersing meniscus lens members is therefore greater by a factor of oneat the side of the image than at the side of the object.

While taking into consideration the position of the infrared image, itis advantageous to form the dispersing meniscus-shaped system portion orcomponent of the image side inner lens component of at least three lenselements of suitable glass selection as shown in Example 3 6.

It is within the framework of the invention to also divide the lenscomponent A, as taught in Example 8. Cemented surfaces can also remainuncemented and separated from one another by small air spaces, insofaras there does not occur any total reflection of the bundle of light raysparticipating in the formation of the image. In the event that in one orthe other lens component there is introduced an air layer or space whichdoes not appreciably influence the total efficiency of the objective,then, in this manner, divided lens components, within the teachings ofthe invention, are to be considered as a single component.

The optical data of the various objectives depicted in FIGS. 1 to 9 aregiven in the following tables, in which each Example indicates adjacentthereto the number of the corresponding Figure illustrating it.

EXAMPLE 1 (FIG. I)

n, v, r 185.00 L d,== 15.00 1.55232 63.5

r,-+ 49.00 I 36.30 r 7l.00 L, d,- 35.00 1.74400 44.8

- I, 1.20 r 40.95 L, d,= 19.00 1.67790 55.2

r 48.30 L da- 7.10 1.57500 41.5

1,: 6.24 r.= w L, d,= 6.00 1.51680 64.2

l,- 2.00 r 39.15 L, 11 5.00 1.71736 29.5

r -100.00 L. d;- 22.00 1.71300 53.8

l 33.00 r 45.30 g 1 d 12.00 1.71300 53.8

Distance r,, Image I 50.8

EXAMPLE 12 (FIG. 7)

Distance r,-,- lmage 48.0

EXAMPLE 13 (FIG. 8)

' I. I 4.00 r 85.00 L," d,- 6.00 1.61293 37.0

r 280.00 L d 18.00 1.69100 54.9

I. I 25.20 r,; 48.00 L d I 4.20 1.51680 64.3

I. I 12.60 r 54.00

d I 3.40 1.51680 64.3 r,,- 104.81 Distance r,, Image I 26.4

EXAMPLE 14(F1G. 9)

"a "a r 202.73 L, d 3.9 1.58313 59.5

I, I 38.8 r, 67.90 L, I d, I 30.1 1.75084 27.5

I, I 5.8 58.20 L, d, I 27.2 1.72875 54.2 r; 58.20 L. d. I 9.5 1.6300050.7

l, I 5.8 1387.00 L, d I 2.5 1.48750 70.4

r 55.80 L, d. I 30.1

r,,-. 28.45 L, d, I 9.7 1.74000 28.2

I I 24.3 r,, 43.80 L. d,, 0.8 1.61272 58.6 r,, 130.00 L, d,- 7.0 1.6129337.0

I, I 29.3 up 53.60 L d I 6.0 1.60361 53.6

r 93.80 Distance r,.- Image I 25.6 What 1s claimed is:

l. A wide-angle objective composed of six components separated from eachother by air spaces and located three at the object side of a diaphragmand three at the image side of such diaphragm, said six lens componentstaken in consecutive order from the side of the object comprising:

a. a first lens component composed of at least one dispersing meniscuslens member curved towards the object side;

b. a second lens component which follows a larger air space composed ofa meniscus lens component curved towards the object side;

, c. a third lens component which follows an air space which is greaterthan 0.005 F and smaller than 0.17 F, said third lens componentpossessing a collecting refractive index and having a strongly convexcurved outer surface facing the object side having a radius of curvaturelying in a range between 0.26 and 0.95 F, and further having a concavecemented surface facing the object side which at the side of the objectpossesses a greater refractive index than at the image side and has aradius of curvature lying in a range between 0.30 and 0.72 F;

d. a fourth lens component which follows the diaphragm space, saidfourth lens component having a collecting refractive index and astrongly convex curved outer surface which faces the image andpossessing a radius of curvature between 0.24

and 1.05 F and further a concave cemented surface facing the image andwhich at the side of the image exhibits a greater refractive index thanat the side of the object and has a radius of curvature which is in therange between 0.28 and a fifth lens component which follows an air spacewhich is greater than 0.00 and smaller than 0.25 F,

said fifth lens component comprising a meniscus lens component which iscurved towards the image and assembled from at least one dispersing andcollecting lens;

. a sixth lens component which follows a larger air space and composedof at least one dispersing meniscus lens member curved towards theimage;

g. the spacing of both outer surfaces of said cemented third and fourthcollecting lens components which face away from the diaphragm being in arange between 0.35 and 0.90 F;

h. the radius of curvature of said convex surface of said third lenscomponent being in a range amounting to one to three times theaxialthickness of said third lens component;

i. the radius of curvature of said convex surface of the fourth lenscomponent being in a range between one to three times the axialthickness of said fourth lens component; and j. theoutside' radius ofthe objective at the side of the image being less than the outsideradius at the side of the object. 4 2. A wide-angle objective as definedin claim 1, wherein the difference of the radii of curvature of theboundary surfaces of the air space between said fourth lens componentand said fifth lens component is greater than 1.35 times the differencebetween the radii of curvature of the boundary surfaces of the air spacebetween said second lens component and said third lens component.

3. A wide-angle objective as defined in claim 1, wherein the number ofindependent dispersing meniscus lens members is greater at the imageside by a factor of one than at the object side.

4. A wide-angle objective as defined in claim 1, wherein said first lenscomponent comprises a plurality of dispersing meniscus lens memberscurved towards the object side.

5. A wide-angle objective as defined in claim 1, wherein said sixth lenscomponent comprises a plurality of dispensing meniscus lens memberscurved towards the image.

1. A wide-angle objective composed of six components separated from eachother by air spaces and located three at the object side of a diaphragmand three at the image side of such diaphragm, said six lens componentstaken in consecutive order from the side of the object comprising: a. afirst lens component composed of at least one dispersing meniscus lensmember curved towards the object side; b. a second lens component whichfollows a larger air space composed of a meniscus lens component curvedtowards the object side; c. a third lens component which follows an airspace which is greater than 0.005 F and smaller than 0.17 F, said thirdlens component possessing a collecting refractive index and having astrongly convex curved outer surface facing the object side having aradius of curvature lying in a range between 0.26 and 0.95 F, andfurther having a concave cemented surface facing the object side whichat the side of the object possesses a greater refractive index than atthe image side and has a radius of curvature lying in a range between0.30 and 0.72 F; d. a fourth lens component which follows the diaphragmspace, said fourth lens component having a collecting refractive indexand a strongly convex curved outer surface which faces the image andpossessing a radius of curvature between 0.24 and 1.05 F and furtherpossesses a concave cemented surface facing the image and which at theside of the image exhibits a greater refractive index than at the sideof the object and has a radius of curvature which is in the rangebetween 0.28 and 0.60 F; e. a fifth lens component which follows an airspace which is greater than 0.00 and smaller than 0.25 F, said fifthlens component comprising a meniscus lens component which is curvedtowards the image and assembled from at least one dispersing andcollecting lens; f. a sixth lens component which follows a larger airspace and composed of at least one dispersing meniscus lens membercurved towards the image; g. the spacing of both outer surfaces of saidcemented third and fourth collecting lens components which face awayfrom the diaphragm being in a range between 0.35 and 0.90 F; h. theradius of curvature of said convex surface of said third lens componentbeing in a range amounting to one to three times the axial thickness ofsaid third lens component; i. the radius of curvature of said convexsurface of the fourth lens component being in a range between one tothree times the axial thickness of said fourth lens component; and j.the outside radius of the objective at the side of the image being lessthan the outside radius at the side of the object.
 2. A wide-angleobjective as defined in claim 1, wherein the difference of the radii ofcurvature of the boundary surfaces of the air space between said fourthlens component and said fifth lens component is greater than 1.35 timesthe difference between the radii of curvature of the boundary surfacesof the air space between said second lens component and said third lenscomponent.
 3. A wide-angle objective as defined in claim 1, wherein thenumber of independent dispersing meniscus lens members is greater at theimage side by a factor of one than at the object side.
 4. A wide-angleobjective as defined in claim 1, wherein said first lens componentcomprises a plurality of dispersing meniscus lens members curved towardsthe object side.
 5. A wide-angle objective as defined in claim 1,wherein said sixth lens component comprises a plurality of dispensingmeniscus lens members curved towards the image.